PDE5 Inhibitors

Findings from a multicenter, randomized, double-blind, placebo-controlled study are consistent with previously reported data showing that tadalafil (Cialis) improves lower urinary tract symptoms associated with BPH. However, the benefit cannot be explained by effects on pressure-flow urodynamics, researchers reported at the European Association of Urology annual congress.

The prospective study randomized 200 men to treatment with tadalafil, 20 mg, or placebo once daily for 12 weeks. At baseline and study completion, patients underwent urodynamics studies and completed International Prostate Symptom Score (IPSS) questionnaires.

The difference between groups in the change from baseline to endpoint in detrusor pressure at peak urinary flow rate (Pdet@Qmax) was eval- uated as the primary endpoint. This pressure-flow parameter was essentially unchanged from baseline in both study groups, and the between- group difference of change (-2.18 cm H₂O) was not statistically significant (p=.325), reported lead author Stephen R. Kraus, MD, chief of the section of female urology, neurourology, and voiding dysfunction. University of Texas Health Science Center, San Antonio.

Additional pressure-flow and free-flow end points similarly showed minimal changes in both groups and no statistically significant differences between groups. Overall, tadalafil had no detri mental effect on bladder function.

In both treatment groups, mean IPSS was about 22 at baseline and had improved at study completion. However, there was a 4.22 point greater reduction among tadalafil recipients in comparing the change between groups, and this was statistically significant (p<.001).

“First, it is important to emphasize that tadala fil is only approved by the FDA for the treatment of erectile dysfunction,” Dr. Kraus cautioned. “That said, in men with LUTS secondary to BPH, results from several studies now show its use results in a statistically significant and clini cally relevant symptomatic improvement based on the IPSS.

“While the mechanism underlying that ben efit remains to be explained, tadalafil treatment also appears to have favorable safety in men with LUTS secondary to BPH, and several ongoing manufacturer-sponsored phase III studies are further evaluating that potential indication.”

During the initial ED studies, men receiving tadalafil also reported an improvement in urinary symptoms. A pilot study in men with LUTS secondary to BPH incorporating uroflow measurements to investigate this effect was undertaken, but improvements in flow rates were not observed. The present study was undertaken as a rigorous evaluation of pressure-flow urodynamics.

“In the realm of BPH research, this trial was unique because the urodynamics studies were performed in a standardized fashion ensured by administering an extensive methodology training program at each center,” Dr. Kraus noted.

Dr. Kraus is a consultant for Eli Lilly and was paid for his participation in the clinical trial development and implementation.